We have mapped the protostellar jet HH 211 in 342 GHz continuum , SiO ( J = 8 - 7 ) , and CO ( J = 3 - 2 ) emission at \sim 1 ^ { \prime \prime } resolution with the Submillimeter Array ( SMA ) .
Thermal dust emission is seen in continuum at the center of the jet , tracing an envelope and a possible optically thick compact disk ( with a size < 130 AU ) around the protostar .
A knotty jet is seen in CO and SiO as in H _ { 2 } , but extending closer to the protostar .
It consists of a chain of knots on each side of the protostar , with an interknot spacing of \sim 2 ^ { \prime \prime } - 3 ^ { \prime \prime } or 600 - 900 AU and the innermost pair of knots at only \sim 1 ^ { \prime \prime } _ { { } ^ { \textrm { . } } } 7 or 535 AU from the protostar .
These knots likely trace unresolved internal ( bow ) shocks ( i.e. , working surfaces ) in the jet , with a velocity range up to \sim 25 km s ^ { -1 } .
The two-sided mass-loss rate of the jet is estimated to be \sim ( 0.7 - 2.8 ) \times 10 ^ { -6 } M _ { \odot } yr ^ { -1 } .
The jet is episodic , precessing , and bending .
A velocity gradient is seen consistently across two bright SiO knots ( BK3 and RK2 ) perpendicular to the jet axis , with \sim 1.5 \pm 0.8 km s ^ { -1 } at \sim 30 \pm 15 AU , suggesting a presence of a jet rotation .
The launching radius of the jet , derived from the potential jet rotation , is \sim 0.15 - 0.06 AU in the inner disk .